The present invention relates generally to implants for use in bone surgery and more particularly to a method and apparatus for trochanter fixation.
In many reconstructive procedures of the hip, the greater trochanter with its attached abductor musculature is often resected from the proximal femur and then retracted to permit the physician to approach the joint. After the femoral head is replaced with a prosthetic femoral component, the greater trochanter is relocated and fastened in place. Sound reattachment of the greater trochanter to the main shaft of the femur is necessary for the hip operation to provide good functional results. In this regard, sound reattachment of the greater trochanter requires that the greater trochanter be immobilized relative to the proximal femur until the bone has had time to fully heal.
Existing methods for reattachment of the greater trochanter include the use of U-bolts, bolts and clamps, and plates and screws. Perhaps the most common prior art method is to wire the greater trochanter in position using various techniques, such as a rigid H-shaped implant disclosed in U.S. Pat. No. 4,269,180 to Dall et al. These methods, however, have several drawbacks.
These drawbacks are primarily associated with the shape of the implant and the manner in which the forces exerted by the wires are directed into the femur. Many of the available implants lack an anatomical shape that conforms to the natural shape of the femur, rendering it more difficult to properly locate the implant and attach the wires in a manner that directs a clamping force into the femur in an optimal manner. In use, the abductor muscle applies a substantial force to the implant and wires, sometimes causing the greater trochanter to migrate relative to the proximal femur or the wires to be pulled through the bone against which it bears. In either event, proper fixation of the greater trochanter to the proximal femur is not obtained.
It is one object of the present invention to provide an anatomical implant for the reattachment of a resected portion of a bone to a proximal portion of a bone.
It is another object of the present invention to provide an anatomical implant for the reattachment of a resected greater trochanter to a proximal femur.
It is a further object of the present invention to provide an implant for the reattachment of a resected greater trochanter that positions a plurality of attachment wires so as to direct a clamping force into the femur in an improved manner.
It is yet another object of the present invention to provide a method for fixing a resected greater trochanter to a proximal femur.
In one form, the present invention provides an implant for use in fixing a resected portion of a bone to a proximal portion of the bone. The implant includes an anatomically shaped plate member having a generally straight first portion and a second portion. The first portion has an anatomically shaped bone receiving groove on its inner side and at least one lower wire receiving groove on its exterior side. The bone receiving groove is adapted to receive a generally straight portion of the proximal portion of the bone. The second portion is coupled to the first portion at a first end and terminates at a distal end in at least one inwardly directed hook-shaped member. The second portion is anatomically shaped to generally match the contour of an end portion of the bone. The hook-shaped member includes at least one tine that is adapted to abut the resected portion of the bone to prevent the resected portion from migrating from the straight portion of the proximal portion of the bone. A method for fixing a resected greater trochanter to a proximal femur is also provided.